1. Technical Field
The present disclosure relates to a display device, a method for driving the display device, and an electronic apparatus including the display device.
2. Description of the Related Art
Display devices such as liquid crystal display devices include transmissive display devices and reflective display devices. Transmissive display devices display images with light transmitted through a liquid crystal panel by emitting the light from a backlight provided on the back side of the liquid crystal panel. Reflective display devices display images with reflected light obtained by reflecting light emitted from the front of a liquid crystal panel toward the liquid crystal panel.
A technique has been developed by which a white pixel serving as a fourth sub-pixel is added to conventional red, green, and blue sub-pixels serving as first to third sub-pixels, as disclosed in Japanese Patent Application Laid-open Publication No. 2012-22217 (JP-A-2012-22217). With this technique, the white sub-pixel increases luminance, thereby causing images to be brightly displayed and improving visibility of the display device. In particular, images on a reflective display device are darker than those on a transmissive display device in some cases, so that the white pixel is added so as to able to appropriately brighten the images.
According to the technique of JP-A-2012-22217, an expansion coefficient for expanding an input signal is varied according to brightness of the input signal. Accordingly, the expansion coefficient increases as the brightness decreases, that is, as the gradation level decreases, and the expansion coefficient decreases as the brightness increases, that is, as the gradation level increases. As a result, the luminance on the low gradation side increases, and the visibility of the display device is improved. However, according to the technique of JP-A-2012-22217, the luminance always increases at a constant rate (expansion coefficient) with respect to saturation. Hence, lowering (deterioration) in display quality, such as gradation collapse and/or a change in color, may be caused on the high saturation side.
For the foregoing reasons, there is a need for a display device, a method for driving the same, and an electronic apparatus that can reduce deterioration of images.